5. Hayes Process Macro - Model 4 | #Mediation Analysis with Single Mediator

A single-mediator mediation model in Hayes’ PROCESS Macro (Model 4) is used to test whether organizational culture affects organizational performance indirectly through organizational commitment. The core finding is that culture has a statistically significant indirect effect on performance via commitment, and the direct effect remains significant as well—meaning the relationship is best described as partial, not full, mediation. This matters because it identifies commitment as a mechanism linking culture to performance, which can guide interventions aimed at improving outcomes.

The session first lays out mediation terminology: the total effect of an independent variable (X) on a dependent variable (Y) is split into a direct effect (C′) and an indirect effect through a mediator (M). In the notation used, the path from X to M is labeled a, the path from M to Y is labeled b, and the direct effect of X on Y while M is included is labeled C′. The indirect effect is computed as a×b, and the total effect is the sum of the direct and indirect components (C′ + a×b).

With the variables specified—culture as X, commitment as M, and organizational performance as Y—the analysis is run in PROCESS Macro with Model 4 and one mediator. The output is interpreted through two regression equations: one predicting commitment from culture, and another predicting performance from both culture and commitment. Culture significantly predicts commitment (path a), with the model accounting for about 37% of the variance in commitment (R² = .37). Commitment significantly predicts performance (path b), and together culture and commitment account for about 43.13% of the variance in performance (R² = .4313).

For the direct effect, the coefficient for culture predicting performance while commitment is present (C′) is significant (reported as 0.2917), with confidence intervals that do not cross zero. The indirect effect is then calculated by multiplying the relevant path coefficients: a = 0.6041 and b = 0.4531, yielding an indirect effect of about 0.2736. The total effect is reported as the sum of direct and indirect effects, approximately 0.5653. To confirm mediation, the analysis relies on bootstrapped confidence intervals for the indirect effect; because the interval does not include zero, the indirect effect is significant.

Finally, the session distinguishes mediation types. Full mediation would require the direct effect to be non-significant once the mediator is included, indicating culture affects performance only through commitment. Here, the direct effect is significant alongside the indirect effect, so the model indicates partial mediation. The sign of the effects also determines whether mediation is “complementary” or “competitive.” Because the direct and indirect effects share the same positive sign (all relevant coefficients are positive), the mediation is classified as complementary. The results are summarized by reporting the culture → commitment → performance chain, the total effect, direct and indirect effects with confidence intervals and t statistics, and the conclusion that commitment mediates the culture–performance relationship partially.